Self-closing valve with adjustable activation

ABSTRACT

The valve ( 1 ) exhibits an external body ( 2 ) affording an internal cavity ( 3 ) which terminates externally of the external body ( 2 ) with an outlet section ( 4 ) and an inlet section ( 5 ). A piston ( 7 ) is slidingly and sealedly housed inside the cavity ( 3 ), and defines a first chamber ( 8 ) and a second chamber ( 9 ) therein. The piston ( 7 ) internally exhibits a channel ( 11 ) communicating with the first chamber ( 8 ), through a first hole ( 12 ), and the second chamber ( 9 ), through a second hole ( 13 ). Internally of the channel ( 11 ) the piston ( 7 ) exhibits means for intercepting the fluid ( 15 ) for slowing fluid passage from the first chamber ( 8 ) to the second chamber ( 9 ).

The device of the invention is applicable, for example, to the field ofwater-cleaning machines but offers considerable versatility, so that itcan be used in any hydraulic circuit including a positive displacementpump and a device governing a fluid at pressure.

With reference, for example, to water-cleaning machines, over the pastfew years the market has seen an increase in the performance of thesemachines, with increases in pressure and flow rate.

These increases cause some difficulties in the manoeuvrability of thewater guns dispensing the pressurised fluid.

In the prior art, the hydraulic circuit of a water-cleaning machineincludes a pump, preferably positive displacement with pistons,connected downstream through a conduit with a valve, which valve isconnected to a pistol for dispensing the pressurised fluid.

This valve is connected through a further by-pass conduit to the pump.In the briefly above-described configuration, when the gun is shut offthe valve traps the pressurised fluid between the connection conduitwhich joins the valve and the gun, zeroing the pressure between valveand pump in the by-pass circuit, as the by-pass discharge is opened.

When the gun opens the flow in the connection conduit between valve andgun is abruptly freed and a reaction force is generated on the gunhandle having an opposite direction to the fluid dispensing direction.

The types of valves used in these types of circuit are pressureisolators, which operate with very short reaction times and with usuallyhigh reaction forces on opening of the gun.

The main aim of the present invention is to provide a self-closing valvewhich can be regulated and which is able to reduce the entity of thereaction force during the transitory period of opening a pressurisedfluid dispensing device such as, for example, a gun for water-cleaningmachines. In this context the term “transitory” is taken to mean thetime that passes from the start of dispensing to reaching the workingflow-rate of the gun.

A second aim of the present device is to provide an adjustableself-closing valve which includes the possibility of regulating theduration of the transitory period of opening of a pressurised fluiddispensing device such as, for example, a gun for water-cleaningmachines.

A further aim of the present device is to provide an adjustableself-closing valve which, by limiting the reaction forces that come intoplay, enables a greater working life of the mechanical organs that makeup the hydraulic circuit, which are no longer subject to sudden shocks.

These aims and advantages and more besides are all attained by theinvention as it is characterised in the claims that follow.

Further characteristics and advantages of the present invention willbetter emerge from the detailed description that follows of a preferredbut non-exclusive embodiment of the invention, illustrated purely by wayof non-limiting example in the accompanying figures of the drawings, inwhich:

FIG. 1 is a lateral view in section of the adjustable self-closing valveof the invention in the rest position;

FIG. 2 is a lateral view in section of the adjustable self-closing valveof the invention in the closed position;

FIG. 3 illustrates a first application of the adjustable self-closingvalve of the invention mounted in parallel with a traditional controlvalve of a fluid dispenser device;

FIG. 4 illustrates a first application of the adjustable self-closingvalve of the invention mounted in series with a traditional controlvalve of a fluid dispenser device;

FIG. 5 is a detailed view of a constructional detail of the adjustableself-closing valve.

With reference to the figures of the drawings, 1 denotes in its entiretyan adjustable self-closing valve.

The valve 1 exhibits an external body 2 having a predominant directionalong an axis X-X.

The external body 2 internally comprises a cavity 3 terminatingexternally with respect to the external body 2 with an outlet section 4and an inlet section 5.

The outlet section 4 is preferably oriented along the axis X-X while theinlet section 5 is preferably oriented transversally with respect to theoutlet section 4.

A seating 19 is present at the outlet section 4, in which seating 19 anannular striker element 20 is housed, affording a hole 21 which ispreferably arranged coaxially to the axis X-X; exiting fluid ischannelled through this hole 21.

The seating 19 further exhibits an increase in section 25 housing anannular body 18 located in contact with the striker element 20, whichannular body 18 exhibits an internal diameter which is smaller than theexternal diameter of the striker element 20.

Opposite to the outlet section 4 there is a cap 6 which is connectableto the external body 2 by means of a threaded coupling.

A piston 7 sealedly slides internally of the cavity 3 in a paralleldirection to the axis X-X.

The piston 7 defines a first chamber 8 internally of the cavity 3, whichfirst chamber 8 is located downstream of the piston 7, and also definesa second chamber 9 upstream of the piston 7.

The first chamber 8 communicates between the inlet section 5 and theoutlet section 4, while the second chamber faces the cap 6.

The piston 7, activated reciprocally by viscous forces and contrasted byelastic means 10 and a pressure difference to close or open the outletsection 4, internally exhibits a channel 11 having a development axisthat preferably coincides with the axis X-X, thus being coaxial to thehole 21 of the striker element 20.

The channel 11, which enables communication between the first chamber 8and the second chamber 9, is defined by a first tract 22, a first hole12, able to place the first chamber 8 and the first tract 22 incommunication, and a second hole 13, enabling communication between thesecond chamber 9 and the first tract 22.

The first tract 22 exhibits, in proximity of the second chamber 9, achange in section which defines a first portion 16 and a second portion17.

The first portion 16 has a greater external diameter than the secondportion 17 and is side-by-side with the hole 12 (FIG. 5).

The first hole 12 and the second hole 13 pass through the piston 7 andare directed transversally with respect to the first tract 22, whichthey are in communication with.

The piston 7 exhibits a stem 14, coupled on the first tract 22, whichstem 14 is preferably conical and can close the hole 21 by viscous dragdue to fluid which, passing in outlet through the hole 21, drags thestem 14 with it.

The piston 7 further exhibits means for intercepting 15 the fluid whichact on the first tract 22 to slow down the fluid passage from the firstchamber 8 to the second chamber 9.

The means for intercepting 15 are defined in a preferred embodiment by acylindrical body 24 coupled with play internally of the first tract 22.

The cylindrical body 24 could be replaced by any body that is solid inrevolution, such as for example a sphere or any extruded solid, such asfor example a parallelepiped, as long as the aspect of the coupling withplay is respected with the first tract 22 in which it is inserted.

The elastic means 10, acting on the piston 7 and located in the firstchamber 8, exhibit a side which is in striking contact with the piston 7and an opposite side which is in striking contact on the outlet section4.

In more detail, the elastic means 10 are preferably defined by a spring26 exhibiting a first end 26 a striking on the annular body 18 and asecond end 26 b striking on the piston 7.

In this configuration in the adjustable self-closing valve 1 the piston7 is mobile alternatively from a rest position, in which the piston 7 isin striking contact with the cap 6 due to the action of the elasticmeans 10 and the stem 14 partially intercepts the hole 21 (FIG. 2), in aclosed position in which the piston 7 closes the outlet section 4, i.e.the stem 14 completely intercepts the hole 21 (FIG. 1).

Owing to the high pressures to which the valve can be subjected, thevalve closure is obtained mostly via the piston 7, which exhibits at theoutlet 4 section thereof a bevelled projection 27 which in the valveclosed position strikes on a seating 28 afforded on the external body 2.

In this configuration with the closure effected by the piston 7, thegeometric characteristics of the stem 14 can be varied, as can those ofthe seating 20, to obtain various stem closure action times.

The adjustable self-closing valve is normally open and self-closes whenthe first chamber is pressurised.

FIG. 3 shows a first example of a hydraulic circuit for water cleanerswhich is provided with an adjustable self-closing valve 1 mounted inparallel with respect to a traditional by-pass valve 34, which governs afluid dispenser device 35.

A motor 30 is present in the hydraulic circuit, which motor 30 powers apositive displacement pump 31 connected upstream to a water deliverypipe 32.

A first pipe 33 emerges from the pump 31, which first pipe 33 is inhydraulic connection with the traditional by-pass valve 34 and theadjustable self-closing valve 1.

The traditional by-pass valve 34 is connected to a fluid dispenserdevice 35 and also to a first by-pass conduit 36 for the water deliverypipe 32. The adjustable self-closing valve 1 is hydraulically connectedto the water delivery pipe 32 through a second by-pass conduit 37.

FIG. 4 shows a second example of a hydraulic circuit for water-cleaningmachines having an adjustable self-closing valve 1 mounted in serieswith a second, flow sensitive valve 34′ of known type that governs afluid dispenser device 35.

In this further example of a hydraulic circuit a motor 30 supplies apump 31 connected upstream to a water delivery pipe 32.

A first pipe 33 emerges from the pump 31, the first pipe 33 being inhydraulic connection with the flow sensitive valve 34′.

The flow sensitive valve 34′ is connected downstream to a fluid deliverydevice 35 and with a by-pass conduit 36 to the water delivery pipe 32.

The adjustable self-closing valve 1 is hydraulically interpositionedbetween the flow sensitive valve 34′ and the fluid delivery device 35and exhibits a second by-pass conduit 37 connected to the water deliverypipe 32.

The integrated hydraulic circuit of the device operates as in thefollowing description.

The traditional by-pass valve 34 causes an upstream pressure drop tonegligible pressure with the fluid regulation device 35 closed anddownstream an isolation of the circuit.

When the delivery device 35 is closed, the traditional by-pass valve 34closes fluid transmission thereto and by-passes the fluid to the waterdelivery conduit 32 via the first by-pass conduit 36.

A part of the fluid delivered by the pump 31 reaches the adjustableself-closing valve 1 through the inlet section 5.

The valve 1 receives the fluid in the first chamber at a practicallyzero pressure.

In this configuration the adjustable self-closing valve 1 is in a restposition and the elastic means 10 keep the piston 7 in striking positionagainst the cap 6 (see FIG. 1).

The means for intercepting the fluid 15 are still.

The stem 14, connected to the piston 7, allows exit of inletting liquidfrom the valve 1 as pressure levels are very low.

When the delivery device 35 is closed, the valve 1 by-passes theinletting liquid to the water delivery conduit 32 through the secondby-pass conduit 37.

When the delivery device 35 is opened, the traditional by-pass valve 34closes the first by-pass conduit 36, enabling transmission of fluidtowards the delivery device 35.

The fluid transmitted by the pump 31 is separated and a part thereofreaches the delivery device 35 while the remaining part thereof goes tothe valve 1 via the inlet section 5.

The fluid inletting to the valve 1 exits in drips from the outletsection as the valve 1, in the rest position, has the stem 14 located onthe striker element and partially occluding the hole 21.

The drip-passage of the exiting fluid causes a viscous drag and apressure drop which causes the stem 14 to translate and thus close thehole 21.

At the same time as the stem 14 translates, the piston 7 also translatescausing a depression in the second chamber 9.

The fluid inletting to the first chamber 8 passes through the channel 11of the second chamber 9.

The passage of the fluid is slowed down due to the action of the meansfor intercepting 15 acting on the channel 1 1.

At this stage the valve 1 reaches the closed position and the secondby-pass conduit 37 is closed so that the pressurised fluid is sent inits totality by the traditional by-pass valve 34 to the dispenser device35.

The retarded closure of the valve 1 enables working pressure to bereached by the fluid dispenser device 35 very gently, avoiding theemergence of reaction forces.

The integrated hydraulic circuit of the device functions as follows.

The flow sensitive valve 34′ enables, when the dispenser device 35 isclosed, a lowering of pressure in the whole circuit, to negligiblelevels. When the dispenser device 35 is closed the flow-sensitive valve34′ by-passes the fluid through the first by-pass conduit 36, excludingboth the dispenser device 35 and the valve 1.

In this configuration there is a small residual pressure on thedispenser device 35 and therefore on the inlet 5 of the valve 1.

The valve 1 is open in the rest position, with the piston 7 strikingagainst the cap 6 under pressure of the elastic means 10, while themeans for intercepting 15 are still.

By opening the fluid dispenser device 35 the flow-sensitive valve 34′closes the first by-pass conduit 36.

The fluid sent to the flow-sensitive valve 34′ separates and in partgoes to the dispenser device 35 and in part reaches the valve 1 via theinlet section 5.

In this case too a dripping of water crosses the hole 21, generating aviscous drag and a pressure drop which cause the stem 14 to close theoutlet section 4.

At the same time as the outlet section 4 is closed there is a passage offluid, slowed by the means for intercepting 15, from the first chamber 8to the second chamber 9.

Once the valve 1 is closed the fluid is totally conveyed by the flowsensitive valve 34 to the dispenser device 35.

The subdivision of the second tract 11 b, on which the cylinder 24translates, into the two portions 16 and 17 enables a differentcommutation of the valve 1 from the rest position to the closedposition.

As the first portion 16, facing the second chamber 9, has a greaterexternal diameter than the second portion 17, the drip-through of thewater will happen faster from the second chamber 9 to the first chamber8, i.e. during the return run from the closed position to the restposition.

This makes the valve 1 faster to reset, which is a necessary conditionfor it to correctly perform the following opening of the dispenserdevice 35.

The valve 1 exhibits the further advantage of managing the duration ofthe closure transition.

This is possible by acting on the cap 6 which determines a reduction inthe volume of the second chamber 9 and at the same time causes avariation in the piston 7 run.

In order to minimise the size of the whole hydraulic circuit, the valve1 can be advantageously united with the traditional by-pass valve 34 orthe flow-sensitive valve 34′, so as to form a single body, whilemaintaining the same configuration as the circuit illustrated in FIGS. 3and 4.

1). A self-closing valve with adjustable activation, comprising: anexternal body (2) developing along an axis X-X, internally exhibiting acavity (3) which terminates externally of the external body (2) in anoutlet section (4) and an inlet section (5); a piston (7), slidablealong the axis (X-X) in the cavity (3) from a rest position, in whichthe piston (7) permits exit of fluid from the outlet section (4), to aclosed position in which passage of fluid into the outlet section (4) isprevented, which piston (7) defines internally of the cavity (3) a firstchamber (8) located downstream of the piston (7) and a second chamber(9) located upstream of the piston (7), which piston is actuated byviscous forces, by elastic means (10) and by a pressure difference forclosing or opening the outlet section (4), and which piston (7) isinternally provided with a channel (11) set between and in communicationwith the first chamber (8) and the second chamber (9); characterised inthat the piston (7) comprises: a stem (14), preferably conical,positioned in the outlet section (4); means for intercepting (15) thefluid, acting on the channel (11) for slowing the passage of fluid fromthe first chamber (8) to the second chamber (9). 2). The valve of claim1, characterised in that the means for intercepting (15) the fluid aredefined by a cylindrical body (24) coupled with play internally of thechannel (11). 3). The valve of claim 1, characterised in that thechannel (11) is defined by a first tract (22) having an axis which isparallel to the axis (X-X), and a first hole (12) and a second hole(13), each of which first hole (12) and second hole (13) developstransversally to the axis (X-X), and which first hole (12) enableshydraulic communication between the first chamber (8) and the firsttract (22) and which second hole (13) enables hydraulic communicationbetween the second chamber (9) and the first tract (22). 4). The valveof claim 1, characterised in that the external body (2) exhibits,opposite the outlet section (4), a cap (6) facing the second chamber (9)and being connectable thereto by means of a threaded coupling. 5). Thevalve of claim 1, characterised in that the first chamber (8) is incommunication with the inlet section (5) and the outlet section (4). 6).The valve of claim 1, characterised in that the elastic means (10),which act on the piston (7) and which are located in the first chamber(8), exhibit an end which strikes against the piston (7) and an oppositeend which strikes on the outlet section (4). 7). The valve of claim 1,characterised in that the outlet section (4) exhibits a seating (19) inwhich a striker element (20) is housed, having a hole (21) which iscoaxial to the first tract (22) and which enables communication betweenthe outlet section (4) and the first chamber (8). 8). The valve of claim7, characterised in that the seating (19) also includes an increase insection (25) on which an annular body (18) is housed in contact with thestriker element (20) and facing the first chamber (8), which annularbody has a smaller internal diameter than an external diameter of thestriker element (20). 9). The valve of claim 8, characterised in thatthe elastic means (10) positioned in the first chamber (8) and acting onthe piston (7) are defined by a spring (26) exhibiting a first end (26a) striking against the annular body (18) and a second end (26 b) whichstrikes against the piston (7). 10). The valve of claim 7, characterisedin that the piston (7), when located in the rest position, exhibits aprojection (27) which is distanced from the seating (28) while the stem(14) is against the striker element (20), partially occluding the hole(21). 11). The valve of claim 7, characterised in that the piston (7),when located in the closed position, exhibits the projection (27)striking against the seating (28) and the stem (14) totally occludingthe hole (21). 12). The valve of claim 3, characterised in that thefirst hole (12) and the second hole (13) pass through the piston (7) andare transversally oriented with respect to the first tract (22). 13). Ahydraulic circuit for dispensing a pressurised fluid, comprising: amotor (30) powering a pump (31), which pump (31) is connected upstreamwith a water delivery pipe (32); a traditional by-pass valve (34),connected downstream of the pump (31) via a first pipe (33), whichby-pass valve (34) exhibits a by-pass conduit (36) connected to thewater delivery pipe (32) and hydraulically connected to a fluiddispenser device (35); characterised in that it comprises theself-closing valve (1) with adjustable activation of claim 1, whichvalve (1) is connected upstream to the first pipe (33) via a secondby-pass conduit (37), the valve (1) being connected in parallel to thetraditional by-pass valve (34). 14). A hydraulic circuit for dispensinga pressurised liquid, comprising: a motor (30) powering a pump (31),which pump (31) is connected upstream with a water delivery pipe (32); aflow sensitive valve (34′), connected downstream of the pump (31) via afirst pipe (33), which flow sensitive valve (34′) exhibits a by-passconduit (36) connected to the water delivery pipe (32) and hydraulicallyconnected to a fluid dispenser device (35); characterised in that itcomprises the self-closing valve (1) with adjustable activation of claim1, which valve (1) is hydraulically interpositioned between the flowsensitive valve (34′) and the fluid dispenser device (35), and whichvalve exhibits a second by-pass conduit (37) connected to the deliverypipe (32), the self-closing valve (1) with adjustable activation beingconnected in series with the flow sensitive valve (34′).